help with aux oil cooler line needed, how tight does this fitting have to be? what to do if it starts to kink?? Options

[DRPHIL914]

alright so here is the back story- reinstalled the motorand transmission, didnt pay attenrtion to where the oil cooler was at the time, but it was on floor and not up under where it should be, so only choice was to disconnect the oil lines at the cooler, put the cooler back up where it was supposed to be mounted(it is now!) and then reconnect the lines - ok so that is where i am- and now i cant get the fitting tightened back down the last turn with out the line spinning with the fitting!!!! so it starts to twist and kink.
I have tried to hold it with my hand, and a pliers but i am afraid i will damage the line.
SO what do i do?? its attached at the other end on the adapter plate and not accessible with out a huge amount of extra work.
How much pressure is on this when the thermostat opens up and pushes oil thru the aux cooler? if this is not super tight ammi going to be blowing oil thru? and all over? its pretty tight, but should i loosen it up and put plumbers tape on the threads? if i hold the soft line with a pliers until the last quarter turn am i going to damage it?

I am truely at the pint with this that if its complicated i dont have time and its not going to get done - and if it leaks its not either - i need a solution - if this is high pressure i will have to get it tight, if not then i can probably get by-

Thanks